1. Field of the Invention
The present invention relates generally to waveguides, and more particularly, but not by way of limitation, to a method of and apparatus for coupling a waveguide flange assembly to a waveguide.
2. Description of Related Art
Waveguides are commonly used for transmitting electromagnetic wave energy from one point to another. One of the more extensive commercial uses of waveguides is the transmission of electromagnetic signals from transmitting or receiving equipment. This transmission may occur, for example, between an equipment shelter and an antenna, often mounted on a tall tower. In general, the waveguide consists of a hollow metallic tube of defined cross-section, uniform in extent in the direction of propagation. Within the hollow tube, the electric and magnetic fields are confined, and, since the tubes are normally filled with air, dielectric losses are minimal. Commercially available waveguides may be either of the rigid wall or flexible variety and their cross sectional shapes may be rectangular, circular and elliptical. Such waveguide shapes are, for example, disclosed in U.S. Pat. Nos. 3,822,411 to Merle and 4,047,133 to Merle.
It is generally necessary for waveguides to be coupled to transmitting or receiving equipment at some point. Both the design of the waveguide, as well as coupling systems for use therewith, are critical to the efficiency of the overall system and thus certain design parameters must be applied For example, it is well known to preclude the generation of field variations with height and their attendant unwanted modes. It is similarly well-known to securely mount a waveguide within a waveguide flange connector in order to prevent reflection losses and impendence mismatches. Reliable and secure mountings are not, however, always easy to accomplish. It is for this reason that waveguide flange and coupling assemblies have been designed and implemented for connecting waveguides one to the other as well as to receiving or transmitting equipment, Due to the variety of applications and variations in the design of such transmitting and receiving equipment as well as variations in the designs of waveguides, the waveguide flange and coupling assembly has become an area of intense design focus. Not the least of the reasons for the above referenced focus is the functional efficiency of the waveguide flange and coupling assembly. It is well known that trouble may occur either between the waveguide and its flange or between the two mating flanges of coupled waveguides as well as between a waveguide and equipment being connected thereto. Possible problems which may be encountered include reflected power, high VSWR (voltage standing wave ratio), power leakage and arcing. It is thus critical to provide the appropriate coupling mechanism and methods of assembly for use therewith when linking waveguides to one another or to transmitting or receiving equipment.
Waveguide connectors including flange and coupling assemblies exemplifying prior designs are set forth and disclosed in U.S. Pat. No. 3,374,450 to Stewart (the '450 patent) as well as U.S. Pat. No. 3,500,264 to Floyd (the '264 patent). The '450 patent discloses a waveguide flange and coupling assembly and outlines various aspects of waveguide connection construction. A plurality of clamping elements including a collar and flange member permit waveguide sections to be more easily assembled one to the other and both rigid and flexible waveguides are addressed. Likewise the '264 patent entitled “Connections Means For Waveguide Means” also discloses a method of and apparatus for connecting together sections of waveguides without soldering. U.S. Pat. No. 3,821,670 assigned to Hughes Aircraft Company discloses a “universal type of waveguide flange” aligning and quick release assembly for coupling and decoupling abutting waveguide flanges. The above-referenced functional efficiency and substantially loss free connection aspects are similarly addressed in this reference.
The above-referenced patents address in particular the connection of waveguides one to the other. It is also important to provide an appropriate coupling mechanism with waveguides connected to transmitting and receiving equipment. In that regard, it is typical in the industry to manufacture waveguides, whether rigid or flexible, in standard lengths and shapes. Flanges are generally permanently mounted at one or both ends to allow for attachment to other waveguide sections or telecommunications equipment. Such waveguide flange and coupling assemblies are generally necessary in order to assemble the waveguide sections into a desired array and/or to desired equipment in order to transmit the electromagnetic wave energy between select points. The design of the waveguide flange for the waveguide flange coupling assemblies is thus critical in this aspect.
As stated above, not all transmitting and receiving equipment and not all waveguide sections are manufactured under the same design specifications. It has thus been common to manufacture and stock waveguide sections having different waveguide flange and coupling assemblies permanently affixed on the ends thereof. Certain applications will specify one kind of waveguide flange coupling assembly while another application may specify another. These variations in waveguide couplings can produce both manufacturing and inventorying problems because virtually identical sections of waveguides may be manufactured and then inventoried with different waveguide flange and coupling assemblies on the ends thereof. Some waveguide and flange assemblies will be immediately utilized while others remain in inventory until a particular demand arises. From a commercial efficiency standpoint, this is not a cost-effective approach.
Waveguide and waveguide flange coupling assemblies are critical to the telecommunication industry and necessitate similar production planning and inventory considerations relating to that of other telecommunications equipment. Parts must be kept in stock for particular applications despite the frequency of use. In a competitive economic environment it is, however, incumbent upon manufacturers and suppliers of equipment such as waveguides and waveguides flange adaptors for the telecommunication industry to be able to provide the requisite parts in a relatively short period of time. One approach to reducing inventory capital is to manufacture fewer parts having unique applications. The present invention provides such an approach by utilizing a waveguide flange adaptor capable of multiple applications.